Propagación sexual y asexual de Rhaphithamnus spinosus (espino azul), en Patagonia Andina

Abstract

Rhaphithamnus spinosus is an evergreen, thorny shrub with violet flowers and violet colored nucleus fruit; endemic from the north of the Andean Patagonian forest. Previous works indicate that the seeds have a physiological and mechanical dormancy in their fruit. The objective was to evaluate the methods for sexual and asexual propagation of the species. The viability of the seeds was analyzed with a germination and 2,3,5- triphenyltetrazolium tests. Four pre-germination treatments were tested: T1: Cold-wet stratification for 60 days, (T2): Scarification with sandpaper + cold-wet stratification-60 days, T3: Scarification with sandpaper + soak 1000 ppm gibberellic acid (GA3) for 24 hs and T4: Scarification with sandpaper + soak water / 24 hs as a control in two seed samples. Seeds were sown at 18 °C, with a photoperiod of 12 hours and subsequently sown in a multicell tray. The agamic method consisted in hardwood cuttings that were cut during autumn, and placed in multicell trays, treated with a 1500 ppm indole-3-butyric acid (IBA) solution, with basal heating (20 ºC±2) and mist. In sexual propagation, the germination percentages per treatment were: T1: 4.81 %, T2: 6.29 %, T3: 47.78 % and T4: 2.59 %. Growth in height and ramifications were analyzed. Asexual propagation reached 96 % rooting at 90 days, and plants were then transferred to 3 L pots. It is concluded that the application of combined pre-germination treatments improves the germination percentage. These results suggest the possibility for professional propagation and container cultivation